Characterization and regulation of the gene expression of amino acid transport system A (SNAT2) in rat mammary gland.

Full Abstract

Amino acid transport via system A plays an important role during lactation, promoting the uptake of small neutral amino acids, mainly alanine and glutamine. However, the regulation of gene expression of system A [sodium-coupled neutral amino acid transporter (SNAT)2] in mammary gland has not been studied. The aim of the present work was to understand the possible mechanisms of regulation of SNAT2 in the rat mammary gland. Incubation of gland explants in amino acid-free medium induced the expression of SNAT2, and this response was repressed by the presence of small neutral amino acids or by actinomycin D but not by large neutral or cationic amino acids. The half-life of SNAT2 mRNA was 67 min, indicating a rapid turnover. In addition, SNAT2 expression in the mammary gland was induced by forskolin and PMA, inducers of PKA and PKC signaling pathways, respectively. Inhibitors of PKA and PKC pathways partially prevented the upregulation of SNAT2 mRNA during adaptive regulation. Interestingly, SNAT2 mRNA was induced during pregnancy and to a lesser extent at peak lactation. beta-Estradiol stimulated the expression of SNAT2 in mammary gland explants; this stimulation was prevented by the estrogen receptor inhibitor ICI-182780. Our findings clearly demonstrated that the SNAT2 gene is regulated by multiple pathways, indicating that the expression of this amino acid transport system is tightly controlled due to its importance for the mammary gland during pregnancy and lactation to prepare the gland for the transport of amino acids during lactation.

Learn Faster Today Improve your study skills

Author information

Author/s: López, Adriana (A); Torres, Nimbe (N); Ortiz, Victor (V); Alemán, Gabriela (G); Hernández-Pando, Rogelio (R); Tovar, Armando R (AR);

Affiliation: Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: American journal of physiology. Endocrinology and metabolism (Am J Physiol Endocrinol Metab), published in United States. (Language: eng)

Reference: 2006-Nov; vol 291 (issue 5) : pp E1059-66

Dates: Created 2006/10/09; Completed 2006/11/21; Revised 2007/11/15;

PMID: 16787963, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Amino Acid Transport Systems - genetics; metabolism
Amino Acids, Neutral - metabolism
Animals
Cyclic AMP-Dependent Protein Kinases - antagonists & inhibitors; metabolism
Enzyme Inhibitors - pharmacology
Estradiol - pharmacology
Female
Gene Expression Regulation - physiology

Lactation - physiology
Mammary Glands, Animal - physiology
Progesterone - pharmacology
Protein Kinase C - antagonists & inhibitors; metabolism
RNA Stability - physiology
Rats
Rats, Wistar
Signal Transduction - drug effects; physiology

Associated Chemicals: Amino Acid Transport Systems (0) ; Amino Acids, Neutral (0) ; Enzyme Inhibitors (0) ; SNAT2 protein, rat (0) ; Estradiol (50-28-2) ; Progesterone (57-83-0) ; Cyclic AMP-Dependent Protein Kinases (EC 2.7.11.11) ; Protein Kinase C (EC 2.7.11.13)

These are the highest related articles currently in the database:

See 100+ related articles.